Chicago Mayor Rahm Emanuel, the former chief of staff to President Barack Obama, has a blunt message to the White House on gun control: Don’t leave your friends holding the bag.

Twice in his career Emanuel has helped Democratic presidents deliver signature legislative achievements early in their terms only to watch Democrats get killed in the ensuing mid-term election. It happened to Bill Clinton on the 1994 crime bill, which included an assault-weapons ban. Then, it happened again on the 2010 health care law.

Now, moderates have reason to be wary if Obama comes calling, asking for a tough vote on gun control.

“Don’t walk away from them during the political season,” Emanuel said at a Center For American Progress forum on Monday morning. “Support them.”

Emanuel’s plea comes as the White House prepares to release the recommendations of Vice President Joe Biden’s task force on guns. On Monday, the president, who has said he will take executive action to implement parts of his plan, acknowledged the political thicket that gun-control advocates face.

“Part of the challenge we confront is that even the slightest hint of some sensible responsible legislation in this area fans this notion that somehow here it comes, and everybody’s guns are going to be taken away,” he said at the last press conference of his first term.

A White House spokesman did not immediately reply to a request for comment about whether Obama would provide political cover to lawmakers who back gun-control measures.

If legislation moves through Congress — and that remains a big “if” — moderate Democrats from gun-loving parts of the country will have to calculate whether it is best to stand with the president in trying to enact new restrictions or oppose him. It was Emanuel, then in Congress, who recruited many of the since-defeated class of 2006 and class of 2008 Democrats from swing districts who felt abandoned by the party after casting votes for the health care law.

“Was there any cover? No,” said a House Democratic chief of staff. “People lost their seats over that vote.”

For that reason and others, Emanuel’s voice may carry more weight than others in the White House. In between serving in the House and winning election as Chicago’s mayor, he was Obama’s first White House chief of staff. And, always aware of the delicate politics of the issue, he has undergone his own revolution — a 360-degree turn — on gun control.

He was part of the Clinton White House team that pushed the crime bill, and its assault-weapons ban, through Congress in 1994. But he angered liberals when, as White House chief of staff, he refused to push for a re-enactment of that ban or new gun-control measures. It didn’t take an expert on electoral maps to figure out that Democrats would risk the majority they then held in the House if they tried to push new gun laws in centrist districts they had recently won. The 1994 crime bill was so controversial and so tied in Democratic lore to gun control that the party largely abandoned the issue until Obama took it up in the wake of the Newtown school massacre last month.

According to Daniel Klaidman’s book Kill or Capture, Emanuel hit the roof when he found out in early 2009 that Attorney General Eric Holder had expressed support for a new assault-weapons law. It had been part of the president’s platform, but it would also wreak havoc on the moderates Emanuel had recruited to help win and expand the Democratic majority in the House. “The chief of staff sent word to Justice that Holder needed to ‘shut the fuck up’ on guns,” Klaidman wrote.

Now, as mayor of a city that had more than 400 gun-related homicides in 2012, Emanuel is back cracking down on guns. He favors a renewal of the assault-weapons ban and background checks for purchasers — whether they buy in stores or at gun shows. He announced Monday that Chicago’s pension funds will sell off investments in gun-manufacturing companies, though it was not immediately clear how much, if any, city money is actually tied up in gun-manufacturing companies.

Emanuel’s re-conversion into the gun-control camp brought disbelief in some circles.

Alec MacGillis, a writer for The New Republic, Tweeted “Wait, is this the same Rahm who promoted anti-gun control candidates in ‘06 and urged Obama admin to stay away from the issue?”

It is, but an older and, perhaps, wiser version.

Rather than taking sides, he wants moderates to vote for gun control legislation and liberals to help them on the campaign trail.